The present invention relates to a track zero sensor of a floppy disc driver (FDD) which is one of peripheral equipments of a computer, particularly to a circuit being capable of detecting track zero of a floppy disc driver by means of the current detected from a stepping motor used for driving a head.
In general, a track zero sensor of the floppy disc driver, as shown in FIG. 1, includes a light emitting diode D1 and a photo transistor Q1. When a head of a disc driver shades the light beam radiated from the light emitting diode D1, the photo transistor is turned off, producing the logic low signal.
In this case, a FDD controller provides a track zero signal C1 by combining the outputs of the photo transistor Q1, a direction signal A1 and a step signal B1.
Recently, however, as FDD driving units have a tendency to be compact, thin and light, design of the FDD controller becomes simpler. Nevertheless, the conventional FDD driving apparatus shown in FIG. 1 cannot keep up with the recent tendency due to the use of photo sensors.